Combustion engine and pump unit



Jan. 7, 1941. L R 2,228,097

COMBUSTION ENGINE AND PUMP UNIT Filed Jan. 13, 1939 3/ ii I f J0? 7 $197 m" 27 J4 I6 26 v A5" JZ 3 INVENTCR Warner 75/er BY M,DM,Nan/WnfEd/m1d ATTORNEYS Patented Jan:\7, 1941 UNITED i STATES PAITENT OFFICE 2,228,091 COMBUSTION ENGINE AND PUMP UNIT Switzerland Application January 13, 1939, Serial No. 250,771 In Switzerland February '3, 1938 6 Claims. (o1. 123-10 This invention relates to a combination of a combustion engine, particularly a-two-stroke engine, and a scavenging pump connected 'to and driven by the engine to supply scavenging air to the engine. In the combination combustion engine and scavenging air pump of the invention, each power cylinder is supplied with scavenging air from a pump unit comprising a pair of pumps driven by and coordinated tr al the action of the engine. More particularly, eath pump unit comprises two double-acting pumps, one above the other, driven by the engine and preferably at a stroke shorter than the stroke of the power piston. The pump unit is preferably arranged sothat the upper pump is positioned above the scavenging ports leading from the pump unit to the power cylinder and the lower pump is below the ports. Each pump is provided'with one or more pressure valves and one or more suction valves and they maybe so arranged that the pressure or delivery valves are on the side near the engine. An intermediate chamber is arranged between the pumps into which scavenging air is forced through the pressure valves and the chamber is in direct engagement with valves controlling the passage of scavenging air from the chamber to the power cylinder.

An embodiment of the apparatus of the in-- vention is shown schematically in the accom- 3o panyingdrawing, in which Fig. 1 is a vertical section through a two-stroke combustion engine and pump unit for supplying the engine with scavening air; i

Fig. 2 is a sectional view along the line 2--2 of Fig.4; and

Fig. 3 is a fragmentary view partly in section along the line 3-3 of Fig. 1,' showing one cylinder and its directly connected pump unit.

In the apparatus illustratedin the drawing, the

engine I has a power piston 2 in the power cylinder 3. The power piston has a piston rod 4 connected to a cross head 5 and connecting rod 6 which engages the crankshaft 1. The power cyl inder 3 has the usual exhaust ports 8 leading into the exhaust manifold 9 and ports In for the introduction of charging and scavenging air.

The pumpunit I5 of the invention is attached along onesideofthe power cylinder and comprises an upper pump having a cylinder l6 and piston l1 and a lower pump having a cylinder l8 and piston l9. Each pump piston is mounted upon a pump piston rod 20 connected to a rotat able slide block 2| mounted in a slot 22 of the lever 23 which is mounted at one end to the ad-- justable pivot 24, and the other end connects through the coupling 25 to the cross head 5, The adjustable pivot 24 comprises a bolt or shaft 26 mounted in the'block 21 which is-adjustably slidable in the slot 28 by means of the ahustment screw 29. The block 2|, slotted and pivoted lever 23. and coupling 25 comprise a linkage operatively interconnecting the cross-head 5 to the'rod 20.

Each of the pump cylinders l6 and I8 connects through the suction valves 30 and. 30' with the 10 conduits- 3I- and 3|, leading to a source of air and through the dliyery or discharge valves 32 and, 32' to the intermediate chamber 33and the conduit34, respectively. The intermediate chamber 33is preferably arranged between the pumps, 15 and valves 35 controlling the passage of scavenging and charging air into the ports 10 are mounted within the intermediate chamber.

shown in Fig. 2, the duct or conduit 34 into which AS best the scavenging air under pressure is, forced 20 through valves 32' from the two pumps, leads directly into the intermediate chamber.

As shown in the drawing, the pump unit I5 is attached along one side of each power cylinder and the action of the pumps is coordinated to the 25 action of thepower piston. After ignition of the fuel, the power piston2' moves downwardly moving the piston rod 20 and pump pistons l1 and I9 downwardly opening the suction valves 30 and 30' drawing air into the pump cylinders l5 and I8, 30 respectively, through the air conduits 3| and 3|. This action compresses the air previously drawn into the pump cylinders forcing it out through the pressure valves 32 and 32' into the chamber 33 and conduit 34, respectively. The air forced into 35 conduit 34 flows into the'intermediate chamber 33. When the piston 2 clears the exhaust ports 8, the gas passes through into the exhaust conduit s causing the pressure in the cylinder 3 to be less than the pressure in the intermediate chamber 33. 4o

' This greater pressure in the intermediate chamber over the pressure in the power cylinder causes the valves 35 to open and permit the scavenging and charging air to flow into the cylinder 3. Any suitable valve of known construction which will v. open and close due to pressure differences on the two Sides thereof. may be used, as valves 35. When the power piston reverses and moves upwardly,the

5 rod 20 moves upwardly and causes the two pump pistons to force air into the intermediate cham- '50 ber in the manner just described. The pump pis-.; tons preferably have a shorter stroke than. the power piston, are coordinated with the power piston, and the; pump stroke may be increased or decreased. 5

The combination oi. apparatus in accordance with the invention gives a low air speed in consequence of the low speed of the pump pistons and provides a short length 01' the air ducts between the pressure side and inlet into the engine. The pump unit may be applied in combination with both single acting and double acting engines.

I claim:

1. The combination with a combustion engine and pump for the production of scavenging air for the engine which comprises a. pump unit for each power cylinder of the engine connected to the engine, the pump unit having two pumps in spaced relation with each pump piston thereof mounted on and driven by the same piston rod, a power piston in the power cylinder, means for driving the pump pistons incoordination with the power piston, an intermediate chamber between the pumps, means for passing scavenging air from the pumps into the intermediate chamber, an inlet port for scavenging air leading into the power cylinder, and means connecting the intermediate chamber to the inlet ports whereby scavenging air is passed into the power cylinder.

tons.

2. Apparatus according to claim 1 in which the pump unit is constructed and arranged so that the pump pistons travel at a shorter stroke than the power piston.

3. Apparatus according to claim 1 in which the intermediate chamber is directly in front of the inlet ports leading to the power cylinderand one pump is above the chamber and one pump below the chamber.

4. Apparatus according to claim 1 in which pressure operated valves are mounted in the in- -termediate chamber to control the passage of WERNER TOBLER. 

